You might consider the idea of creating a custom post type called ticker. On the custom post type, add a custom field (input field) and store it as the value. Then one option would be to use code of this nature in your homepage template:
<?php $args = array(
'numberposts' => 5, // how many posts will be in the ticker
'post_type' => 'ticker',
'post_status' => 'publish' ); ?>
<?php $posts = get_posts( $args ); ?>
<?php foreach($lastposts as $post) : setup_postdata($post); ?>
<div class="ticker">[custom ticker field]</div>
<?php endforeach; ?>
Before you can do that though, you would have to set up the custom post type. This is one of the most concise tutorials on making custom post types and adding fields to them. This article explains how to set up custom post types from scratch.
http://thinkvitamin.com/code/create-your-first-wordpress-custom-post-type/
One of the args to pay attention to here is: show_ui (should we display an admin panel for this custom post type)
Or if you don’t want to sort out all that code, you could try to use some combination of these 2 plugins:
http://wordpress.org/extend/plugins/custom-post-type-ui/
http://wordpress.org/extend/plugins/custom-field-template